State of the art substrate coatings used are usually hydrophilic polymers, some members of this group being polyethers, e.g. polyethyleneglycol; polysaccharides, such as hepaiin or dextran; polyalcohols, e.g. polyvinyl alcohol; or also polyamides, as for example polyacrylamide.
Thin hydrogel layers from carboxylated polysaccharides have proofed themselves for biosensory pur U.S. Pat. No. 5,436,161), since these do not only shield the sensor surface against nonspecific interactions, but also make it possible through the carboxyl functionalities to efficiently immobilize different biomolecules.